/sim/view[*] that it finds. It's not only unnecessary that view definitions
have subsequent indices, but aircraft are now *requested* to use indices
100++. /sim/view[0] .. /sim/view[99] are reserved for the system. (Not
that we'd ever need that many, This is just a convention, it's nowhere
hard-coded.)
- replace the string operations for property paths by method calls & other
improvements
I have done a patch to eliminate the jitter of 3D-objects near the viewpoint
(for example 3D cockpit objects).
The problem is the roundoff accuracy of the float values used in the
scenegraph together with the transforms of the eyepoint relative to the
scenery center.
The solution will be to move the scenery center near the view point.
This way floats relative accuracy is enough to show a stable picture.
To get that right I have introduced a transform node for the scenegraph which
is responsible for that shift and uses double values as long as possible.
The scenery subsystem now has a list of all those transforms required to place
objects in the world and will tell all those transforms that the scenery
center has changed when the set_scenery_center() of the scenery subsystem is
called.
The problem was not solvable by SGModelPlacement and SGLocation, since not all
objects, especially the scenery, are placed using these classes.
The first approach was to have the scenery center exactly at the eyepoint.
This works well for the cockpit.
But then the ground jitters a bit below the aircraft. With our default views
you can't see that, but that F-18 has a camera view below the left engine
intake with the nose gear and the ground in its field of view, here I could
see that.
Having the scenery center constant will still have this roundoff problems, but
like it is now too, the roundoff error here is exactly the same in each
frame, so you will not notice any jitter.
The real solution is now to keep the scenery center constant as long as it is
in a ball of 30m radius around the view point. If the scenery center is
outside this ball, just put it at the view point.
As a sideeffect of now beeing able to switch the scenery center in the whole
scenegraph with one function call, I was able to remove a one half of a
problem when switching views, where the scenery center was far off for one or
two frames past switching from one view to the next. Also included is a fix
to the other half of this problem, where the view position was not yet copied
into a view when it is switched (at least under glut). This was responsible
for the 'Error: ...' messages of the cloud subsystem when views were
switched.
I have added a --aspect-ratio-multiplier=x.xx option to give some end user
control over the aspect ratio. (This may seem a little strange, but it's a
building block towards the capability of doing asymmetric view frustums in
FlightGear.)
The jitter is most likely caused by the irregular frame rate and CPU clock dependent intervals. There's no easy way around that. I tried some fancy interpolation and all that -- to no avail.
The current chase view respects heading but ignores roll & pitch. And it follows heading without delay, which makes the viewer behave quite strange. This change makes the chase view feel more natural. You aren't fixed behind the plane, but follow all its movements with a delay.
Erik Hofman:
I've decided not to add the patch to preferences.xml in the base package because something feels funny with that. I think there needs to be some more discussion about it.
04Feb. Actually been running since the beginning of January with these
patches. All changes work without crashing with the current base package cvs,
but there are some visual problems with the views (other than pilot view)
without changes to the base package.
As soon as you can build test and commit I can add in those base package
updates that will make it all work nicely. I will also go through all the 3D
Aircraft configs to make sure the change in the "pitch-offset" for cockpit
views (see below) are made to maintain current behavior.
Here are the files (changes listed below):
http://www.spiderbark.com/fgfs/viewerupdate.diffs.gzhttp://www.spiderbark.com/fgfs/viewerupdate.tar.gz
Make locally-used strings local instead of global. (The safety and
cleanliness benefit outweights the slight performance hit. If
performance is an issue, the way these strings are used should be
optimised.) Use existing defined constant instead of a literal
number.
- changed FGSubsystem::update(int) to
FGSubsystem::update(delta_time_sec); the argument is now delta time
in seconds rather than milliseconds
- added FGSubsystem::suspend(), FGSubsystem::suspend(bool),
FGSubsystem::resume(), and FGSubsystem::is_suspended(), all with
default implementations; is_suspended takes account of the master
freeze as well as the subsystem's individual suspended state
- the FDMs now use the delta time argument the same as the rest of
FlightGear; formerly, main.cxx made a special case and passed a
multiloop argument
- FDMs now calculate multiloop internally instead of relying on
main.cxx
There are probably some problems -- I've done basic testing with the
major FDMs and subsystems, but we'll probably need a few weeks to
sniff out bugs.
These are the updates for the View manager properties. Removed the last of
items (within the viewer/viewmgr) hard coded to view number. Added support
for per view configuration of ground level nearplane value. Tower views look
very nice with little or no z-buffer problem in the models. Pilot offset
dialog can be used to move eye in all views.
Synced to CVS 19:36 EDT 2002-04-10 (after this evenings JSMsim and Base
package updates).
Description:
Added FGLocation class which is new home for calculating matrix rotations.
Viewer can now be configured to access rotations created by the model rather
than repeating the same calculations again.
Changed model initialization for the time being so that its location data is
available for the viewer (currently required by other subsystems). At some
point we can move this back to fg_init along with the viewer initialization.
Seperated the update from the draw function in the model code. The viewer
code needs the same matrix data, and moving the update portion at this time
does not increase the number of matrix math iterations.
Moved the model draw so that it always appears "in front" of lights and clouds.
Reogranized viewer update routine for using the FGLocation class and
simplified some more tasks. The routine is fairly easy to follow now, with
the steps ordered and spelled out in comments.
Viewmgr only updates the current (visible) view now, with the exception of an
old reference to "chase view" that will be corrected in forthcoming changes.
Also will be doing some work on the viewmgr outputs.
Model is now clears the z-buffer in all modes. This will be changed with the
next viewmgr update. The only side effect is that models always disappear
when over 5km distant from the eye point (can't really see them anyway:-)).
Other than a flag to indicate "internal" view I don't anticipate the
configuration interface for viewmgr/views will be changed a lot for now. It
is close to done. The next viewmgr update will however rework the outputs so
may change location.
This code will run with the previous version of preferences.xml, but will run
faster with the newer version. I am attaching a preferences.xml that should
not be commited before the code. All the changes are in the /sim/view section
and should show a simpler view configuration that references model locations.
Note that I've added a 2nd tower view in "lookfrom" mode for illustration
purposes. You can look around using the mouse. You may want to remove that or
comment it out.
Tower View and viewer config is in place. Note that the interface is
still in a state of flux. A couple of the config items (namely the
offsets) are still using the old settings. The tower is hard coded
into the base package for a position off the starting runway at KSFO
and is probably not in the right place for there even. Looks pretty
cool though! Tower View is the third view. If you aren't at KSFO
you'll just see blank space in view 3. It's looking through the earth or
something like that :-). Important note: zoom in with a few
hits of the "x" key to see the plane better in tower view.
Think my brain is getting clogged with matrices :-). Well I've got the funky
orientation offset bug out of the model code. In the process the model.cxx
got optimized a bit. At some point we'll need to liberate model.cxx from the
viewer class, but it is no longer hard coded to access the "pilot view" to
get it's data. Instead it uses whatever the "current" view happens to be. I
may try and do that final bit of having models rotate independant of the view
tomorrow night, or start right in on the viewmgr and get a tower view up and
running. You guys have any preference? My brother's family is coming to
visit for a few days so what I don't get done tomorrow night probably won't
get done until after the weekend.
Fix FGViewer::update so that pitch offset and goal pitch offset work
together nicely (the offset was snapping to 90/-90 when only one of
the two was changed).
Viewer improvements from Jim Wilson:
These files get the 3d cockpit working and fix a few issues in the viewer
code.
XYZ offsets are now defined as follows: X -left/right+ (along wing axis), Y
-up/down+ perpendicular to the aircraft, Z is -in/out+ the aircraft's body axis.
I've also done some cleaning up of unused and mostly unusable interfaces,
added commentary to the *.hxx, combined together some duplicate code and
eliminated a couple unecessary operations. I also moved what was left of the
"protected" zone to "private" since we aren't subclassing this anymore.
Description:
This update includes the new viewer interface as proposed by David M. and
a first pass at cleaning up the viewer/view manager code by Jim W.
Note that I have dropped Main/viewer_lookat.?xx and Main/viewer_rph.?xx and
modified the Makefile.am accordingly.
Detail of work:
Overall:
The code reads a little easier. There are still some unnecessary bits in
there and I'd like to supplement the comments in the viewer.hxx with a tiny
bit on each interface group and what the groupings mean (similar but briefer
than what you emailed me the other day). I tried not to mess up the style,
but there is an occasional inconsistency. In general I wouldn't call it done
(especially since there's no tower yet! :)), but I'd like to get this out
there so others can comment, and test.
In Viewer:
The interface as you suggested has been implemented. Basically everything
seems to work as it did visually. There is no difference that I can see in
performance, although some things might be a tiny bit faster.
I've merged the lookat and rph (pilot view) code into the recalc for the
viewer. There is still some redundancy between the two, but a lot has been
removed. In some cases I've taken some code that we'd likely want to inline
anyway and left it in there in duplicate. You'll see that the code for both
looks a little cleaner. I need to take a closer look at the rotations in
particular. I've cleaned up a little there, but I suspect more can be done
to streamline this.
The external declaration to the Quat_mat in mouse.cxx has been removed. IMHO
the quat doesn't serve any intrinsic purpose in mouse.cxx, but I'm not about
to rip it out. It would seem that there more conventional ways to get
spherical data that are just as fast. In any case all the viewer was pulling
from the quat matrix was the pitch value so I modified mouse.cxx to output to
our pitchOffset input and that works fine.
I've changed the native values to degrees from radians where appropriate.
This required a conversion from degrees to radians in a couple modules that
access the interface. Perhaps we should add interface calls that do the
conversion, e.g. a getHeadingOffset_rad() to go along with the
getHeadingOffset_deg().
On the view_offset (now headingOffset) thing there are two entry points
because of the ability to instantly switch views or to scroll to a new view
angle (by hitting the numeric keys for example). This leaves an anomaly in
the interface which should be resolved by adding "goal" settings to the
interface, e.g. a setGoalHeadingOffset_deg(), setGoalPitchOffset_deg(), etc.
Other than these two issues, the next step here will be to look at some
further optimizations, and to write support code for a tower view. That
should be fairly simple at this point. I was considering creating a
"simulated tower view" or "pedestrian view" that defaulted to a position off
to the right of whereever the plane is at the moment you switch to the tower
view. This could be a fall back when we don't have an actual tower location
at hand (as would be the case with rural airports).
ViewManager:
Basically all I did here was neaten things up by ripping out excess crap and
made it compatible as is with the new interface.
The result is that viewmanager is now ready to be developed. The two
preexisting views are still hardcoded into the view manager. The next step
would be to design configuration xml (eg /sim/view[x]/config/blahblah) that
could be used to set up as many views as we want. If we want to take the easy
way out, we might want to insist that view[0] be a pilot-view and have
viewmanager check for that.
